From 44baee9c1983c5a0d357504db89cb5bfa09743e3 Mon Sep 17 00:00:00 2001
From: Rafael Ortiz <rafael.ortiz@redcanary.com>
Date: Mon, 21 Jun 2021 17:43:59 -0400
Subject: [PATCH] `bpf_map_def` from libbpf and iproute2
---
aya/src/bpf.rs | 32 +++-----------------------------
aya/src/obj/mod.rs | 44 ++++++++++++++++++++++++--------------------
2 files changed, 27 insertions(+), 49 deletions(-)
diff --git a/aya/src/bpf.rs b/aya/src/bpf.rs
index b513f09b..175798cd 100644
--- a/aya/src/bpf.rs
+++ b/aya/src/bpf.rs
@@ -48,7 +48,7 @@ unsafe_impl_pod!(i8, u8, i16, u16, i32, u32, i64, u64);
#[allow(non_camel_case_types)]
#[repr(C)]
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, Default)]
pub(crate) struct bpf_map_def {
// minimum features required by old BPF programs
pub(crate) map_type: u32,
@@ -57,34 +57,8 @@ pub(crate) struct bpf_map_def {
pub(crate) max_entries: u32,
pub(crate) map_flags: u32,
// optional features
- pub(crate) inner_map_fd: u32, // id
- pub(crate) numa_node: u32, // pinning
- pub(crate) map_name: [u8; BPF_OBJ_NAME_LEN],
- pub(crate) map_ifindex: u32,
- pub(crate) btf_id: u32,
- pub(crate) btf_key_type_id: u32,
- pub(crate) btf_value_type_id: u32,
- pub(crate) btf_vmlinux_value_type_id: u32,
-}
-
-impl Default for bpf_map_def {
- fn default() -> Self {
- Self {
- map_type: 0,
- key_size: 0,
- value_size: 0,
- max_entries: 0,
- map_flags: 0,
- inner_map_fd: 0,
- numa_node: 0,
- map_name: [0u8; BPF_OBJ_NAME_LEN],
- map_ifindex: 0,
- btf_id: 0,
- btf_key_type_id: 0,
- btf_value_type_id: 0,
- btf_vmlinux_value_type_id: 0
- }
- }
+ pub(crate) id: u32, // id
+ pub(crate) pinning: u32, // pinning
}
/// The main entry point into the library, used to work with eBPF programs and maps.
diff --git a/aya/src/obj/mod.rs b/aya/src/obj/mod.rs
index 2579dca7..5e548a3a 100644
--- a/aya/src/obj/mod.rs
+++ b/aya/src/obj/mod.rs
@@ -509,33 +509,24 @@ fn parse_map(section: &Section, name: &str) -> Result<Map, ParseError> {
}
fn parse_map_def(name: &str, data: &[u8]) -> Result<bpf_map_def, ParseError> {
- if mem::size_of::<bpf_map_def>() < data.len() {
+ if data.len() > mem::size_of::<bpf_map_def>() {
return Err(ParseError::InvalidMapDefinition {
name: name.to_owned(),
});
}
- let mut map_def = bpf_map_def{
- ..Default::default()
- };
-
- unsafe {
- // std::ptr::copy is const, we can't use it because data.len() isn't known at
- // compile time, this is only safe because we've asserted that data.len()
- // must be <= mem::size_of::<bpf_map_def>(), if you change that check, then
- // you must change this copy
- let mut p = data.as_ptr();
- let mut q = &mut map_def as *mut bpf_map_def as *mut u8;
- for _ in 0..=data.len() {
- *q = *p;
- q = q.add(1);
- p = p.add(1);
+ if data.len() < mem::size_of::<bpf_map_def>() {
+ let mut map_def = bpf_map_def { ..Default::default() };
+ unsafe {
+ ptr::copy(data.as_ptr() as *const bpf_map_def, &mut map_def as *mut bpf_map_def, 1);
+ // id and pinning will be garbage data
+ map_def.id = 0;
+ map_def.pinning = 0;
}
+ Ok(map_def)
+ } else {
+ Ok(unsafe { ptr::read_unaligned(data.as_ptr() as *const bpf_map_def) })
}
-
- Ok(map_def)
-
- //Ok(unsafe { ptr::read_unaligned(data.as_ptr() as *const bpf_map_def) })
}
fn copy_instructions(data: &[u8]) -> Result<Vec<bpf_insn>, ParseError> {
@@ -703,6 +694,19 @@ mod tests {
),
Ok(map_def)
));
+
+ assert!(matches!(
+ parse_map_def(
+ "foo",
+ &[0u8, 0u8, 0u8, 1u8, 0u8, 0u8, 0u8, 2u8, 0u8, 0u8, 0u8, 4u8, 0u8, 0u8, 0u8, 5u8]
+ ),
+ Ok(map_def)
+ ));
+ let map = parse_map_def(
+ "foo",
+ &[0u8, 0u8, 0u8, 1u8, 0u8, 0u8, 0u8, 2u8, 0u8, 0u8, 0u8, 4u8, 0u8, 0u8, 0u8, 5u8]
+ ).unwrap();
+ assert!(map.id == 0 && map.pinning == 0)
}
#[test]